1. Field of the Invention
The present invention relates to a location service providing system and a method thereof, and more particularly to a location service providing system and a method for providing a triggered location request service.
2. Description of the Related Art
With an increase in the demand for various types of location-based location-relation services, various location services have been provided using the location of a mobile terminal, and development for extending the location services to mobile terminals has been achieved. Further, an extension of the location services is expected to be a base of a fourth generation communication service.
In recent years, a triggered location request service has been provided as a location service. In the triggered location request service, a location value of a target terminal periodically or a periodically repeats calculation. If the location value of the target terminal satisfies predetermined conditions, an occurrence fact of a corresponding event is provided to a secure user plane location agent.
A conventional triggered location request service providing method will be explained with reference to FIG. 1. FIG. 1 is a flow chart for describing the conventional triggered location request service providing method. Referring to FIG. 1, a Secure Plane Location Agent (referred to as ‘SUPL AGENT’ hereinafter) 104 requests a triggered location request service from a Home-SUPL Location Platform (H-SLP) 100 using a Mobile Location Protocol Triggered Location Reporting Request (MLP TLRR) in Step 106.
Next, when the H-SLP 100 receives an MLP TLRR message from the SUPL AGENT 104, it goes to Step 108 and judges routing information of a target terminal 102. That is, the H-SLP 100 judges whether the target terminal 102 is roaming and whether the target terminal 102 uses the SUPL.
According to a judgment result of the routing information of the target terminal, the H-SLP 100 goes to Step 110 and transmits a SUPL INITiation (INIT) message (initial location service request message) to the target terminal 102. Here, the SUPL INIT message includes SESSION_ID, which is an ID for discriminating a message exchange of the H-SLP 100 and the target terminal 102, a POSitioning METHOD (POSMETHOD) indicating a positioning method, a trigger type indicator, a proxy, and a non proxy mode indicator indicating a judgment condition of an occurrence or a non-occurrence of an event. In addition, the SUPL INIT message includes a Quality of Positioning (QoP) indicating a required measuring level of location information.
Furthermore, when the target terminal 102 receives the SUPL INIT message from the H-SLP 100, the target terminal 102 proceeds to Step 112 and determines if the H-SLP 100 is in a proxy mode. The target terminal 102 is connected to a data network such a packet data network or a circuit switched data network according to a check result of the proxy mode.
When the target terminal 102 is connected to the H-SLP 100 over the data network, it transmits a SUPL TRIGGERRED START message for starting the triggered location request service to the H-SLP 100 in Step 114. Here, the SUPL TRIGGERED START message includes SESSION_ID, (SUPL Enabled Terminal) SET capabilities, a hash of the received SUPL INIT message (ver), and a Location IDentifier (LID). The SESSION_ID is an identifier for discriminating a message exchange between the H-SLP 100 and the target terminal 102. The SET capabilities indicate a positioning capability. Here, the SET capabilities include a POSMETHOD information, namely, information about a SET-Assisted A-GPS (Assisted Global Positioning System) or a SET-Based A-GPS, information about associated positioning protocols such as a Radio Resource Location services Protocol (RRLP), Radio Resource Control (RRC), or a Telecommunication Industry Association (TIA)-801. FIG. 2 is a view showing an example of POSMETHOD information.
When the H-SLP 100 receives the SUPL TRIGGERED START message, it compares a location measuring capability with information included in the SET capabilities of the target terminal 102 and determines any one suitable positioning method according results of the comparison. Moreover, the H-SLP 100 goes to Step 116 and transmits a SUP TRIGGERED RESPONSET message (triggered location request service response message) including information about the determined positioning method to the target terminal 102. Next, the H-SLP 100 goes to Step 118 and informs the SUPL AGENT 104 using a Mobile Location Protocol Triggered Location Reporting Acquisition (MLP TLRA) that a request for triggered location request service has been received. Then, the H-SLP 100 transmits REQ_ID to be used as Transaction ID while the triggered location request service is being performed. Accordingly, the H-SLP 100 and the target terminal 102 can terminate a current data network connection.
Accordingly, the target terminal 102 goes to Step 120 and judges whether a transmission condition of location information is satisfied. Next, the target terminal 102 is again connected to the data network, when the information transmission condition is satisfied, and transmits a location information reporting message (SUPL POS REPORT message) in Step 122. Here, the SUPL POS REPORT message includes SESSION_ID and Location IDentifier (LID). Accordingly, the H-SLP 100 and the target terminal 102 go to Step 124 and calculates a location of the target terminal 102. The H-SLP 100 and the target terminal 102 go to Step 124 according to whether location information of the target terminal 102 according to the LID included in the SUPL POS REPORT message satisfies a set QoP and calculates a location of the target terminal 102 through the determined positioning method.
When the location of the destination 102 is calculated, the H-SLP 100 goes to Step 126 and reports the location of the target terminal 102 to the SUPL AGENT 104 using a Mobile Location Protocol Triggered Location Report (MLP TLREP) message. Next, when a performance condition of the triggered location request service that the SUP AGENT 104 requested is satisfied, for example, the target terminal 102 reaches a specific location or a set location service performance time is terminated, the H-SLP 100 and the target terminal 102 terminate the triggered location request service.
Accordingly, in the conventional triggered location request service providing method, an occurrence of an event that a location service requester, namely, a SUPL AGENT 104 requests is judged based on a set condition and a procedure for reporting an event occurrence result is repeatedly performed. Consequently, in the conventional triggered location request service providing method, when an H-SLP 100 selects any one from positioning methods included in SET Capabilities of a SUPL TRIGGERED START message in a start Step once, a location of a target terminal 102 is obtained by repeatedly using the same positioning method until the triggered location request service is terminated.
In the conventional method, a location is obtained only once in a conventional immediate service. However, in a case of the triggered location request service, a location should be periodically calculated for a long time such as 24 hours or 72 hours. This can change a situation of the target terminal. For example, while the target terminal 102 obtains a location using a Global Positioning System (GPS), it can be moved to a position in which a GPS signal is not received. Otherwise, while the target terminal 102 acquires a location using distance information, such as Time Difference Of Arrival (TDOA), from cellular Base Stations (BS), it receives distance information for adjacent cells less than 4 and become a state, which cannot use TDOA mode.
Accordingly, in such a case, in the conventional triggered location request service, when positioning method determined start Steps (Steps 114 and 116) of the triggered location request service cannot be used, the triggered location request service generates a positioning error and finishes the service. As a result, the SUPL AGENT 104 cannot receive the service for a required time.